1. Field of the Invention--This invention relates to equipment for loading multiple product units into a sleeve-type package. In particularly, the invention relates to machines for loading cans or bottles or similar cylindrical geometric objects into cartons.
2. Description of the Prior Art--A multitude of apparatus has been used for loading packages with sets of individual product. In particular, the techniques for loading cardboard sleeve-type packages with cans or bottles are manifold.
Cans of beverage are commonly sold in cardboard 12-packs or 24-can cases. The package is a cardboard sleeve into which the cans or bottles are slid from the end. The ends of the sleeve are then folded and glued to seal the individual products in place.
The present invention relates to conveyor belt loaders for such cardboard containers. There is a wealth of patent art in this area, as well as prior art machines which have not been disclosed in patents. The common thread through these disclosures is a central conveyor with transverse bars which separate the open sleeved containers, and hold them as the conveyor moves. Separate side conveyors for feeding cans into the sleeves come in from an angle on either side of the central conveyor. The cans are urged into the container sleeve as the conveyors converge. Two main tasks that must be accomplished are sorting of cans on the side conveyors into sets for loading, and the actual loading of the cans into the sleeves.
The teachings of the prior art are in two main sets.
The first set of prior art involves devices that separate the cans on the outer conveyor with means extending inwardly from the outer side of the apparatus. Some prime examples of this type of structure are U.S. Pat. No. 3,332,199 to Wong, issued Jul. 20, 1967, U.S. Pat. No. 3,300,947 to Fahrenbach, issued Jan. 31, 1967, and U.S. Pat. No. 3,037,431 to McGihon, issued Jun. 5, 1962. Other such art is illustrated by U.S. Pat. No. 2,974,454 to Andre et al., issued Mar. 14, 1961, and U.S. Pat. No. 3,778,959 to Langen, et al., issued Dec. 18, 1973.
In this first class of prior art Various types of fingers or extensions come inwardly from the outside of the device to separate the product, such as cans, into sets. This is done as a first step before the cans are fed into containers on the central conveyor. For example, in the McGihon patent there is a disk with projections which mark off sets of cans. As the disk rotates, a set of cans, for example three in the McGihon disclosure, is isolated between the pairs of fingers. This set then travels down the conveyor into the sleeve.
In the Fahrenbach disclosure, there is a belt having projections which isolate cans. A belt-driven wheel then has a pair of fingers which divide the cans into sets in a manner somewhat similar to McGihon. After separation, the sets of cans are urged into the containers by the merging of the conveyors.
The Wong patent also has a belt bearing fingers which separates sets of cans. The cans are urged into the sleeve by the action of the conveyor merging with the central conveyor.
All of these side-actuated devices have their benefits and their failings. One problem with such side separation of the cans using these prior art techniques is that it was necessarily slow. The complex mechanical arrangement of belts, gears, and projecting fingers had too many moving parts to operate in a rapid manner. It is desirable for today's can loaders to operate in a range of 1,800 to 2,400 cans per minute. Such rapid movement of cans into sleeves cannot be accomplished with these complex belt and finger systems.
A second class of prior art devices involves separator bars or flight bars on the central conveyor which preform a dual task. These bars both 1) hold the sleeved container on the central conveyor, and 2) separate the cans into sets. One example of such dual function flight bar or metering bar is the Thiele Suntan lotion machine, which was commercially available in 1972. This early Thiele machine was shown to have speeded up the process by having a simple mechanism. The flight bar had wedge shaped ends which entered the stream of product as the conveyors merged and thereby metered the product. The flight bars also urged the product into the sleeves which were held by the flight bars.
A second example of this combined technique is U.S. Pat. No. 4,237,673 to Calvert et al., issued Dec. 9, 1980, which operates in the same manner as the Thiele suntan lotion machine. As in the early Thiele machine, the Calvert structure uses dual-purpose central metering bars with wedged shaped tips which preform the dual functions of separating the cans as they come down a diagonal conveyor and also of holding the container sleeves on the central conveyor.
The dual purpose metering bar has prove to be a successful device for years, but it does not allow speeds sufficient to satisfy today's demands.
What is needed in order to speed up loading to meet today's production standards is a can loader which separates the functions of isolating sets of cans for loading and for holding the container sleeves, without using the complex belt, sprocket and finger techniques of the prior art.